tiny optimization to diff-delta

This is my assembly freak side looking at generated code again.  And
since create_delta() is certainly pretty high on the radar every bits
count.  In this case shorter code is generated if hash_mask is not
copied to a local variable.

Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>

diff --git a/diff-delta.c b/diff-delta.c
index 35e517d..45df786 100644 (file)
--- a/diff-delta.c
+++ b/diff-delta.c
@@ -239,7 +239,7 @@ create_delta(const struct delta_index *index,
             const void *trg_buf, unsigned long trg_size,
             unsigned long *delta_size, unsigned long max_size)
 {
-       unsigned int i, outpos, outsize, hash_mask, val;
+       unsigned int i, outpos, outsize, val;
        int inscnt;
        const unsigned char *ref_data, *ref_top, *data, *top;
        unsigned char *out;
@@ -275,7 +275,6 @@ create_delta(const struct delta_index *index,
        ref_top = ref_data + index->src_size;
        data = trg_buf;
        top = trg_buf + trg_size;
-       hash_mask = index->hash_mask;
 
        outpos++;
        val = 0;
@@ -290,7 +289,7 @@ create_delta(const struct delta_index *index,
                struct index_entry *entry;
                val ^= U[data[-RABIN_WINDOW]];
                val = ((val << 8) | *data) ^ T[val >> RABIN_SHIFT];
-               i = val & hash_mask;
+               i = val & index->hash_mask;
                for (entry = index->hash[i]; entry; entry = entry->next) {
                        const unsigned char *ref = entry->ptr;
                        const unsigned char *src = data;